First Battle of Ueda Castle

The First Battle of Ueda Castle (26 August-December 1585) was a battle fought between the Tokugawa and Sanada clans. The 7,000-strong army of Ieyasu Tokugawa and Tadayo Okubo besieged the Sanada stronghold of Ueda Castle, defended by Masayuki Sanada and a much smaller army of 1,200 troops, who were assisted by the Uesugi, in 1585. The Sanada succeeded in thwarting the Tokugawa's siege, and an impressed Ieyasu decided to marry his retainer Tadakatsu Honda's daughter Lady Ina to the son of Masayuki Sanada, Nobuyuki Sanada, as a part of an alliance with the Sanada clan.

Prelude
In the aftermath of the Incident at Honnoji in 1582, warlords fought over control of Japan as the Oda clan's control over the country crumbled with Nobunaga Oda's death. In central Honshu, three clans vied for control of the Kanto region: they were the Tokugawa clan, whose daimyo Ieyasu Tokugawa was a trusted ally of the late Nobunaga; the Hojo, which had emerged as the predominant power in Sagami Province under Ujiyasu Hojo; and the Uesugi, a powerful clan that had been defeated by Nobunaga at the Battle of Tedorigawa in 1577 but was recovering. The Tokugawa fought the Hojo in a fierce battle, and after the battle they decided to agree on a truce. The Hojo would give up some of their land in exchange for the land of the Sanada clan, a vassal of the Tokugawa clan. Daimyo Masayuki Sanada refused to give up the land of his family and turned his back on the Tokugawa, allying with Kagekatsu Uesugi and his clan to fight against their Tokugawa enemies.

Ieyasu Tokugawa led an army of 7,000 troops to seize Ueda Castle, the home of the Sanada clan, which was held by only 1,200 Uesugi troops; the Hojo assisted the Tokugawa army, while the Uesugi assisted the Sanada. Most of the Hojo army was sent to besiege Numata Castle, another stronghold of the Sanada clan, and the Tokugawa army encircled Ueda Castle with its army. The Uesugi sent Kanetsugu Naoe to reinforce the Sanada brothers, and Hideyoshi Hashiba of the Toyotomi clan dispatched his strategist Mitsunari Ishida to assist the Sanada in their resistance against his rival, Ieyasu. Masamune Date, Keiji Maeda, and Magoichi Saika traveled to the castle because of the Sanada clan's pleas for assistance from any warrior in the land, with the three men being landless people who wanted to fight. The Sanada planned to use their brilliant strategies to defeat the larger Tokugawa army, with Kanetsugu Naoe being one of the geniuses behind the ploys.

Battle
The Tokugawa army pushed into the castle as expected, using their might to overwhelm the outer defenses. The Sanada proceeded to counterattack against the Tokugawa by felling trees and using the logs to block the Tokugawa army from sending reinforcements into the castle; the forces in the castle were then ambushed by riflemen and archers. Next, the Tokugawa forces in the villages to the east of the castle fell prey to a fire attack by the Sanada, who were reinforced by their Uesugi allies. With their force combined, they succeeded in driving the Tokugawa army back, destroying their forces on the field. In addition, the Hojo reinforcements were also defeated, and the allied forces were sent into full retreat. Ieyasu was wounded by Masayuki's son, Nobuyuki Sanada, whom Ieyasu decided to spare because of his belief that the next generation would be the leaders of the land, and he did not want to kill a man as gifted as Nobuyuki. The Tokugawa army retreated, leaving the Sanada in control of their castle.

Aftermath
1,300 Tokugawa troops were killed in battle by the Sanada clan, which retained their lands. Ieyasu Tokugawa was so impressed with the Sanada clan's resistance to his powerful army that he arranged for his retainer Tadakatsu Honda's daughter Lady Ina to marry Nobuyuki Sanada to form an alliance with the Sanada. The Sanada and Tokugawa would be allies until 1600, when Nobuyuki sided with the Tokugawa against his father and his brother Yukimura Sanada in the Sekigahara Campaign.